How to Seal Granite Countertops

Granite countertops are durable and require minimal maintenance. However, in order to keep the granite stain resistant, you need to seal it periodically.

Granite is an igneous rock, which means it was formed from molten rock material, specifically quartz, feldspar, mica, amphiboles, and other minerals. As the molten material cooled, tiny gaps formed between the individual crystals, creating pores in the rock. In granite’s natural condition, it absorbs liquid through those pores.

Granite is relatively nonporous compared to other countertop materials, yet it requires a sealer to make the countertop stain-resistant. The sealer creates a barrier that prevents absorption of food and liquids.

How often should I seal the granite?

Typically, granite countertops require the use of a sealant every year.However, various factors contribute to the frequency. One factor is porosity. Lighter colored granite tends to be more porous; therefore, it may require more frequent applications. The second factor is regular wear and cleaning routines. Acidic food spills and acidic cleaning solutions (such as vinegar) gradually degrade granite sealer. In addition, food preparation zones may need sealer more frequently than a raised bar used to serve food.

The final factor is the sealer itself. Some professional grade sealers may last up to ten years. Some tips for determining types of sealers:

If you’re installing new granite, ask the installer which sealer they use and how soon you should reapply it.

If you’re sealing an existing granite countertop, whether using a water-based or solvent-based product, look for the active ingredient fluorocarbon aliphatic resin. Although the product will be more expensive than sealers containing siloxane and silicon, it will provide five to ten years of protection rather than six months to three years. Also, fluorocarbon aliphatic resins repel oil as well as water, so the countertop will be protected from things such as salad dressing spills and greasy pizza boxes.

Perform the Water Test

On a properly sealed granite surface, water should bead up rather than soaking into the pores. To test the surface, pour one or two tablespoons of water on the granite in different areas. After three minutes the water should still be beaded on the top instead of soaking into the granite. Check again after fifteen minutes. Is there a dark mark or ring? If so, it’s time to apply a sealer.

If you apply a sealer before it’s needed, the granite isn’t harmed. However, additional sealer might create a hazy film.

How to Seal Granite

Sealing granite is a simple process that protects the investment you made in your home. Regular sealing, done properly, will prevent stains and keep the natural stone looking its best.

STEP 1 Determine if the countertop requires sealing. Somewhere inconspicuous, like in a corner of the counter, put a few drops of water on top, and a few inches away, put a few drops of oil. After 15 minutes, check to see if the water or oil has seeped in and darkened the granite. If so, proceed with these instructions for how to seal a granite countertop. If not, then the countertop is already sealed, and doing so again will not offer extra protection but only leave an unattractive hazy film.

STEP 2 Clean the countertop 24 hours before sealing, making sure to avoid potentially damaging vinegar, lemon juice, baking soda, bleach, or harsh commercial cleansers. First, take everything off the counter and wipe it down well with a clean, dry microfiber cloth to remove all surface dust. Then, mix one teaspoon of dishwashing detergent and two tablespoons of isopropyl alcohol in a pint spray bottle and fill with cool water. Generously spray the countertop and wipe clean while polishing in a circular motion, using a microfiber cloth. Wait 24 hours before proceeding: The space occupied by the cleaning agent is the same space that the sealant will penetrate, so you must ensure that the cleaning liquid has fully evaporated.

STEP 3Read the sealant’s label thoroughly to understand the application method. Should our instructions vary from the label, defer to the manufacturer. Open nearby windows and doors for ventilation. If it’s raining, do not open windows that could allow rain to hit the countertop; instead, open windows in other areas of the room or in adjacent rooms.

STEP 4Put on rubber gloves and grab the rags. In an area usually covered by a small appliance, test the sealant to ensure it won’t affect the finish. Apply a small amount per manufacturer’s directions, by spraying or pouring onto a cloth and then rubbing it evenly over the test area.

STEP 5Wait the recommended time for the sealant to absorb into the granite, usually 15 to 20 minutes, but sometimes much longer. Don’t let it sit longer than recommended, because that could discolor the stone.

STEP 6If the sealant test area looks great, proceed to Step 7. If it has discolored, wipe up any remaining sealant with a clean rag. Then snap a few photos of the area and show them to an associate at your local home center for advice on a more appropriate product. Once you’ve acquired a new sealant, clean the counter and test the new sealant.

STEP 7If the test was successful, apply the sealant over the entire counter, beginning at one end and working your way to the other. Apply in sections, using a circular motion, of an arm’s length in diameter, to ensure equal coverage throughout. Wait the manufacturer’s recommended time for the product to absorb into the countertop.

STEP 8After the absorption period has passed, wipe any extra sealant off with a clean, soft, dry rag, rubbing in a circular motion. Some products require a second coat, so follow instructions to do so. If the product you use requires one coat, allow it cure, which can take between two and 48 hours. Nonetheless, granite experts recommend waiting a full 48 hours before wiping a newly sealed granite countertop with anything wet. Also, avoid returning any kitchenware to the counter until after the curing period.

STEP 9Once the countertop has fully cured, put your kitchen back in order. Keep the spray bottle of cleaner you created around for periodic use every month or two. For daily cleaning, a dab of dish detergent and a wet rag will get the job done beautifully. Strive to wipe up spills immediately and then dry the countertop to keep your granite looking great.